Switching power supply

Abstract

Disclosed herein is a switching power supply including: N sub switching power supplying unit each converting a direct current (DC) power supplied from a power source into an alternate current (AC) power, boosting or bucking the AC power using a resonant circuit and a contactless transformer, converting the boosted or bucked AC power into a DC power, and outputting the converted DC power; and a balance circuit connecting between the resonant circuits of the N sub switching power supplying units to thereby allow currents to be balanced between the resonant circuits.

1 . A switching power supply comprising:
 N sub switching power supplying units each converting a direct current (DC) power supplied from a power source into an alternate current (AC) power, boosting or bucking the AC power using a resonant circuit and a contactless transformer, converting the boosted or bucked AC power into a DC power, and outputting the converted DC power; and   a balance circuit connecting between the resonant circuits of the N sub switching power supplying units to thereby allow currents to be balanced between the resonant circuits.   
     
     
         2 . The switching power supply as set forth in  claim 1 , wherein the sub switching power supplying unit includes:
 a DC-AC converter converting the DC power supplied from the power source into the AC power;   an AC-DC converter converting the boosted or bucked AC power output from the contactless transformer into the DC power and outputting the converted DC power;   the contactless transformer boosting or bucking the AC power output from the DC-AC converter and outputting the boosted or bucked AC power output to the AC-DC converter; and   the resonant circuit disposed between the DC-AC converter and the contactless transformer to thereby allow a maximum power to be transmitted from a primary winding of the contactless transformer to a secondary winding thereof.   
     
     
         3 . The switching power supply as set forth in  claim 2 , wherein the DC-AC converter is a full bridge converter in which four switching elements are configured in a full bridge scheme. 
     
     
         4 . The switching power supply as set forth in  claim 2 , wherein the DC-AC converter is a half bridge converter in which two switching elements are configured in a half bridge scheme. 
     
     
         5 . The switching power supply as set forth in  claim 2 , wherein the AC-DC converter is a full bridge rectifier circuit in which four diode elements are configured in a full bridge scheme. 
     
     
         6 . The switching power supply as set forth in  claim 2 , wherein the AC-DC converter is a half bridge rectifier circuit in which two diode elements are configured in a half bridge scheme. 
     
     
         7 . The switching power supply as set forth in  claim 2 , wherein output terminals of the AC-DC converters of each of the N sub switching power supplying units are connected in parallel with each other. 
     
     
         8 . The switching power supply as set forth in  claim 2 , wherein output terminals of the AC-DC converters of each of the N sub switching power supplying units are connected in series with each other. 
     
     
         9 . The switching power supply as set forth in  claim 1 , wherein the balance circuit includes N−1 capacitors for balance connecting between the resonant circuits of the sub switching power supplying units that are adjacent to each other to thereby allow the currents to be balanced between the resonant circuits. 
     
     
         10 . The switching power supply as set forth in  claim 9 , wherein the balance circuit further includes a capacitor for balance connecting between the resonant circuits of the sub switching power supplying units that are not adjacent to each other to thereby allow the currents to be balanced between the resonant circuits. 
     
     
         11 . The switching power supply as set forth in  claim 1 , wherein the resonant circuit includes a resonant capacitor and a resonant inductor that are connected in series with each other, and
 the balance circuit includes N−1 capacitors for balance each having one terminal connected between a resonant capacitor and a resonant inductor of a resonant circuit configuring any one sub switching power supplying unit and the other terminal connected between a resonant capacitor and a resonant inductor of a resonant circuit configuring another sub switching power supplying unit that is adjacent to any one sub switching power supplying unit to thereby allow the currents to be balanced between the resonant circuits of the N sub switching power supplying units.   
     
     
         12 . The switching power supply as set forth in  claim 11 , wherein the balance circuit further includes a capacitor for balance having one terminal connected between a resonant capacitor and a resonant inductor of a resonant circuit configuring any one sub switching power supplying unit and the other terminal connected between a resonant capacitor and a resonant inductor of a resonant circuit configuring another sub switching power supplying unit that is not adjacent to any one sub switching power supplying unit to thereby allow the currents to be balanced between the resonant circuits of the N sub switching power supplying units.